Electrochemical fabrication of porous NiCuMoOx electrodes to enhance mass transfer in anion exchange membrane water electrolyzers

초록

The development of efficient non-noble electrocatalysts for alkaline hydrogen evolution reactions requires balancing intrinsic activity, structural stability, and mass transfer. This study demonstrates the electrodeposition of ternary NiCuMoOx composites on carbon paper to utilize the advantages of both the binary Ni-Mo and Ni-Cu systems. Structural characterization revealed that the optimized NiCuMoOx/carbon paper (CP) exhibits an intermediate morphology between the film-like NiMoOx/CP and dendritic NiCuOx/CP, featuring a face-centered cubic NiCu crystalline phase, as confirmed by X-ray diffraction and high-resolution transmission electron microscopy. Electrochemical evaluations in half-cell configurations show that NiCuMoOx/CP achieves a remarkably low hydrogen evolution reaction overpotential of 36 mV at -10 mA cm(-2) and a Tafel slope of 86 mV dec(-1). Under conditions of high current density (>400 mA cm(-2)), the dendritic NiCuMoOx/CP exhibits superior mass transfer owing to enhanced bubble detachment and excellent stability during 12-h chronopotentiometry tests. The anion exchange membrane water electrolyzer achieved a current density of 1.47 A cm(-2) at 2.0 V-cell, attributed to synergistic reduction of kinetic and mass-transfer overpotentials enabled by Mo incorporation and a porous structure. These findings highlight the critical role of ternary composite catalyst in bridging the activity-stability trade-off for industrial-scale electrolyzers.

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